Well if you think about it adding that chainsword would be a good idea.... The power fist wouldn't really be able to smash through the hulk of the armor so they add the chain sword so when they take the shreeding power of it and the immensive power of the fist it would tear through armor like butter....that would be my guess

well the eviscerator does the same thing and its weilded by normal people so that puts a bug in that though also it could be a power chain sword or a suped up one(extra power behind it better teeth and such) just my thoughts